Elon Musk wants to get inside your head. In April, the Silicon Valley billionaire announced plans to launch Neuralink—a company dedicated to developing a brain-to-machine interface to cure brain ailments like paralysis and memory problems and help people compete with robots when the artificial intelligence revolution makes human brains obsolete. Musk says this will be accomplished by implanting tiny electrodes into the brain—allowing for things like downloading and uploading memory and casual brain-to-brain communication.

Leaders in the neurotechnology field welcome Musk’s arrival, while neuroethicists and others urge caution. The endeavor may sound like science fiction, but it’s feasible, says Timothy Deer, president of the International Neuromodulation Society, a nonprofit group of researchers and developers dedicated to using spinal cord stimulation to treat neurological pain. “The cochlear implant was invented 20 years ago, and with electricity and the right frequencies targeting the brain, it allows people to hear,” he says. “That sounded impossible back then.” And great gains require great brains, Deer says. “Ben Franklin didn’t know how to harness electricity, but he and others knew it was the key to something. Now, we know how to use electricity in very specific ways. It’s exciting to see how Mr. Musk might change how we think.”

Humans have been trying to mess with their brain waves to solve diseases since ancient times: The Romans and Greeks used to put electric fish on top of their heads to relieve pain, says Ana Maiques, CEO of Neuroelectrics, a company that develops noninvasive wireless brain monitoring and stimulation technologies.

Zack Lynch, founder of Neurotechnology Industry Organization, a global trade association representing companies involved in neuroscience and brain research, says, “The [human] brain is the most complicated organ on the planet.” The neurotechnology industry produces $165 billion in yearly revenue, he says, but 90 percent of that revenue comes from pharmaceuticals for neurological disorders like Lou Gehrig's disease, or amyotrophic lateral sclerosis, as well as post-traumatic stress disorder and depression. Annual revenue from neurological devices is about $10 billion.

If Musk is successful, he will run into a swamp of ethical issues. “Neuroscience raises questions about technology, art, entertainment, warfare, religion and what it means to be human,” Lynch says. And these considerations will be difficult to address in the short term, says Peter Reiner, professor and co-founder of the National Core for Neuroethics. “Most important is privacy of thought. When a computer is hooked up to me and knows what I’m thinking, that becomes a very challenging area to navigate.” Another issue is what Reiner calls “reason bypassing.” If a device can influence your brain without you perceiving it, are you really making your decisions? He believes society already faces these questions with smartphones: Advertisers are collecting information about users based on their browsing habits and then using that data to try to change their behavior.

Daniel Wilson, a best-selling author and robotics engineer, considers these ethical issues in his novel Amped, which predicts that neurotechnology will cure people with mental disabilities and eventually help them leapfrog beyond human ability. The amplified humans known as “amps” are then discriminated against because the public fears their abilities.

Wilson believes brain-to-machine interfaces will become common, but that they will not diminish the humanity of their users. “People often look at human creations, and we call them unnatural,” Wilson says. “But from my perspective, there’s nothing more natural than a human being creating a tool. Bird’s nests or anything animals do instinctively always seems natural, but we consider it unnatural when a human uses a tool. That’s the most natural thing that a human can do. To put that tool in our bodies is a completely natural extension of what we’ve been doing for millennia.”